1. Field of the Invention
This invention relates to an improved process for converting methanol to ethanol in which a liquid mixture of methanol, water, a Group VIII metal catalyst and a basic inorganic compound is contacted with an atmosphere of carbon monoxide at elevated temperature and pressure.
2. Brief Description of the Prior Art
Ethanol is a well known organic chemical and has a wide variety of industrial applications including use as a solvent for resins, fats and fatty acids and serves as a "building block" for the synthesis of a variety of larger molecular weight organic compounds.
The overall process of converting an organic compound to a higher homologue, by increasing the number of CH.sub.2 units by one, is termed in the art, "homologation".
Processes for homologating methanol to ethanol are known in the art and provide a potential basis for the synthetic production of ethanol to supplement ethanol obtained by fermentation.
However, these processes, as illustrated in the references: Science, Vol. 113, pp. 206-207 (1951); British Pat. No. 951,506 (1964); U.S. Pat. No. 3,248,432 (1966); U.S. Pat. No. 3,285,948 (1966); U.S. Pat. No. 3,356,734 and Belgian Pat. No. 842,430, involve methods of homologating methanol in which gaseous mixtures of carbon monoxide and hydrogen gas are utilized. A method that does not require the use of hydrogen gas, a potentially explosive material, would be highly desirable.
A related reference, "Proceedings of the Symposium on Chemicals and Oil From Coal," Central Fuel Research Institute, June 1972, pages 151 to 158, describes the hydrogenation of coal in the presence of carbon monoxide, water and an inorganic base, such as sodium carbonate, in which a variety of hydrogenated organic products are obtained. However, the process is not described as being effective for producing ethanol in good yield and selectivity.
Another reference, British Pat. No. 733,792 (1955) describes a process in which methanol can be homologated to ethanol by passing a mixture of methanol and steam over a cobalt-thorium-copper heterogeneous catalyst at a pressure of about 100 atmospheres and a temperature of about 200.degree. C. However, the process requires steam as a reactant, and the attendant requirements for its production, for producing a hydrogen source in the reaction.